Background: Sustained attention (SA) is a vital function mediated by the right frontal-parietal cortex. The six letter cancellation task (SLCT) measures SA. Assessment of SA in volunteers undergoing Yoga therapy (YT) training compared to control group is the theme of the present study. Materials and Methods: Sixty healthy volunteers, 48.75 ± 3.86 years of mean age were participated in the present study. Thirty volunteers selected from Swami Vivekananda Yoga Anusandhana Samsthana University, Bengaluru, India were practiced YT for 7 days. They were compared with a control group of 30 healthy volunteers from Sri Devaraj Urs Medical College, Kolar, India matched for the duration of the study, age, gender, and socioeconomic background that were not exposed to YT training but continued their usual college routine during that period. All volunteers were assessed for SA using SLCT. Results: The YT group showed 18.06% significant increase (P = 0.010, paired samples t-test) in total attempted (TA) score on SLCT. Similarly, there was 19.03% significant increase (P = 0.008, paired samples t-test) in net score (NS). However, there was 26.32% decrease in wrongly attempted (WA) score which was statistically not significant (P = 0.637, paired samples t-test). There was no significant change in control group. Increase in TA and NS and decrease in WA is related with enhancement of SA. Conclusion: The results suggest that YT enhances SA in healthy volunteers. Additional well-designed trial with long-term follow-up is needed before a strong recommendation can be made.

Sustained attention (SA) is the capacity to attend to a task in hand for a required period. It is closely associated with task difficulty or complexity.[1] It is closely associated with the mental effort required by the task in hand.[2] The capacities to study and listen to a lecture for an extended length of time are examples of SA. The six letter cancellation task (SLCT) requires SA, as well as the ability to shift attention. The availability of the Indian normative data for the SLCT allowed wider application of this test in clinical practice for studying SA. Yoga comprises a wide range of mind/body practices from postural and breathing techniques to deep relaxation and meditation. Yoga therapy (YT) tailors these to the health needs of the individual. Similarly, YT helps to promote all-round positive health, as well as assisting particular medical conditions such as depression, stress, and anxiety.[3] Particularly, it is more appropriate for many chronic conditions that persist despite conventional medical treatment.[4] Moreover, YT helps in empowering individuals to progress toward improved health, happiness and well-being through the application of the teachings and practices of Yoga.[5] The present study was designed to obtain preliminary estimates of the effectiveness and safety of YT compared with a control group in healthy volunteers.

Materials and Methods

Subjects

Sixty healthy volunteers, 48.75 ± 3.86 years of mean age were participated in the present study. Thirty volunteers selected from Swami Vivekananda Yoga Anusandhana Samsthana (S-VYASA) University, Bengaluru, India were practiced YT training for 7 days. They were compared with a control group of 30 healthy volunteers selected from Sri Devaraj Urs Medical College, Kolar, India matched for duration of the study, age, gender, and socioenvironmental background that were not exposed to YT training but continued their usual college routine during that period.

The YT [6] for 7 days was practiced by YT group [Table 1]. The YT consists of Kriya (cleansing techniques) Sithilikarana Vyayama (loosening and stretching practice), Suryanamaskara (practice of salutation to sun), Asana (posture), Pranayama (breathing practice), and Dhyana (meditation). They were compared with a control group of 30 healthy volunteers (medical college staff) selected from Sri Devaraj Urs Medical College, Kolar, India matched for the duration of the study, age, gender, and socioeconomic background that were not exposed to YT training.

The SLCT consists of a test worksheet which specifies six target letters to be cancelled, and a “working section” consisting of a 22 × 14 array of randomly arranged letters of the alphabets. Study participants were asked to cancel as many of the six target letters in the array as possible in the allotted time of 1:30 min. Participants were told that there are two possible strategies: (i) Canceling all six letters at once or (ii) selecting one target letter out of the six at a time. They were asked to choose whichever strategy suited them. They were also told that they could follow a horizontal, vertical, or a random path according to their choice. Scoring was carried out by a person blind to the details of the data. The total number of cancellations and wrong cancellations were scored and the net score (NS) calculated by subtracting wrong cancellations from total cancellations.[7] Each component measures a different quantity. The total number of cancellations is a measure of motor skill combined with cognitive function. The number of wrong cancellations is a measure of lack of focused attention and mental distractions. NS is a measure of SA.

Statistical analysis

The data were entered into Excel sheet. The level of significance was conducted using P value. P ≤ 0.05 was considered statistically significant. Statistical analysis was performed using SPSS version 10 (Sun Micro solutions, Gujarat, India for PC Windows 2000). The results were expressed as mean ± standard deviation. The Kolmogorov–Smirnov test showed that the data were normally distributed. Hence, paired samples test was used to compare means of the data collected before and after the YT.

Results

The YT group showed 18.06% significant increase (P< 0.01), paired samples t-test) in total attempted (TA) score on SLCT. Similarly, there was 19.03% significant increase (P = 0.008, paired samples t-test) in NS. However, there was 26.32% decrease in wrongly attempted (WA) score which was statistically not significant (P = 0.637, paired samples t-test) [Table 2] whereas there was no significant change in the control group in regard to TA, NS, and WA [Table 3].

Table 2: Six letter cancellation task scores before and after the yoga therapy

Cancellation tasks require visual selectivity and a repetitive motor response.[8] They not only require SA but also visual scanning and activation and inhibition of rapid responses. The present study found a significant increase in SA scores after the YT whereas there was no significant change in control group in regard to TA, NS, and WA. Previous study on SLCT reported cyclic meditation brings about a greater improvement in task performance (NS = 26%, P < 0.001) than supine rest (NS = 14%, P < 0.001).[9]

The significant increase in NS for the YT group on the SLCT suggests that the yoga improves functioning of the right frontal-parietal cortex mediating SA.[6] Similarly, the significant increase in TA by the IYT group suggests improvement in the frontal association areas, where the cognitive function guiding motor skills are located.[10] Decrease in WA suggests that yoga improves functions in the orbitofrontal area of the prefrontal cortex, which is hypothesized to mediate distraction avoidance.[11] Reduced anxiety can improve performance on tasks requiring SA [12] and yoga's anxiety-reducing effects [13] could also have facilitated this. Increase in TA and NS and decrease in WA was related with enhancement of SA [14] and several components in the YT could have contributed to the increase in the YT group's SA scores. Any kind of rhythmic resonance has the power to make the mind more relaxed and peaceful [15] and so improve attention span. Vedic mantras are highly rhythmic and uniformly filled with resonance. Their daily chanting by the YT group may have been partly responsible for the observed increase in the group's SA scores.

Conclusion

The practice of YT enhances SA in healthy volunteers compared to control group. Additional well-designed randomized control trial with long-term follow-up is needed before a strong recommendation on wider acceptance and application of the YT module can be made.

Acknowledgment

Authors would like to acknowledge Swami Vivekananda Yoga Anusandhana Samsthana (S-VYASA) University and Sri Devaraj Urs Medical College, Tamaka, Kolar, Karnataka, India for granting permission to carry out this work.